Method and apparatus to treat conditions of the naso-pharyngeal area

ABSTRACT

A patient&#39;s upper airway condition such as snoring and sleep apnea is treated by selecting a particulate material selected for limited migration within tissue and for encouraging a fibrotic response of tissue to the material. A bolus of the particulate material is injected into the tissue area to structurally stiffen the tissue.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation application of applicationSer. No. 10/629,145, filed Jul. 29, 2003, which is a continuation ofapplication Ser. No. 10/394,887, filed Mar. 21, 2003, which is acontinuation of application Ser. No. 10/190,183, filed Jul. 3, 2002, nowU.S. Pat. No. 6,546,936, which is a continuation of application Ser. No.09/636,803, filed Aug. 10, 2000, now U.S. Pat. No. 6,431,174, whichapplications are incorporated herein by reference.

BACKGROUND

[0002] 1. Field of the Invention

[0003] This invention is directed to methods and apparatuses fortreating conditions of the naso-pharyngeal area such as snoring andsleep apnea. More particularly, this invention pertains to method andapparatus to stiffen tissue of the naso-pharyngeal area.

[0004] 2. Description of the Prior Art

[0005] Snoring has received increased scientific and academic attention.One publication estimates that up to 20% of the adult population snoreshabitually. Huang, et al., “Biomechanics of Snoring”, Endeavour, p.96-100, Vol. 19, No. 3 (1995). Snoring can be a serious cause of maritaldiscord. In addition, snoring can present a serious health risk to thesnorer. In 10% of habitual snorers, collapse of the airway during sleepcan lead to obstructive sleep apnea syndrome. Id.

[0006] Notwithstanding numerous efforts to address snoring, effectivetreatment of snoring has been elusive. Such treatment may include mouthguards or other appliances worn by the snorer during sleep. However,patients find such appliances uncomfortable and frequently discontinueuse (presumably adding to marital stress).

[0007] Electrical stimulation of the soft palate has been suggested totreat snoring and obstructive sleep apnea. See, e.g., Schwartz, et al.,“Effects of electrical stimulation to the soft palate on snoring andobstructive sleep apnea”, J. Prosthetic Dentistry, pp. 273-281 (1996).Devices to apply such stimulation are described in U.S. Pat. Nos.5,284,161 and 5,792,067. Such devices are appliances requiring patientadherence to a regimen of use as well as subjecting the patient todiscomfort during sleep. Electrical stimulation to treat sleep apnea isdiscussed in Wiltfang, et al., “First results on daytime submandibularelectrostimulation of suprahyoidal muscles to prevent night-timehypopharyngeal collapse in obstructive sleep apnea syndrome”,International Journal of Oral & Maxillofacial Surgery, pp. 21-25 (1999).

[0008] Surgical treatments have been employed. One such treatment isuvulopalatopharyngoplasty. In this procedure, so-called laser ablationis used to remove about 2 cm of the trailing edge of the soft palatethereby reducing the soft palate's ability to flutter between the tongueand the pharyngeal wall of the throat. The procedure is frequentlyeffective to abate snoring but is painful and frequently results inundesirable side effects. Namely, removal of the soft palate trailingedge comprises the soft palate's ability to seal off nasal passagesduring swallowing and speech. In an estimated 25% ofuvulopalatopharyngoplasty patients, fluid escapes from the mouth intothe nose while drinking. Huang, et al., supra at 99.Uvulopalatopharyngoplasty (UPPP) is also described in Harries, et al.,“The Surgical treatment of snoring”, Journal of Laryngology and Otology,pp. 1105-1106 (1996) which describes removal of up to 1.5 cm of the softpalate. Assessment of snoring treatment is discussed in Cole, et al.,“Snoring: A review and a Reassessment”, Journal of Otolaryngology, pp.303-306 (1995).

[0009] Huang, et al., supra, describe the soft palate and palatalsnoring as an oscillating system which responds to airflow over the softpalate. Resulting flutter of the soft palate (rapidly opening andclosing air passages) is a dynamic response generating sounds associatedwith snoring. Huang, et al., propose an alternative touvulopalatopharyngoplasty. The proposal includes using a surgical laserto create scar tissue on the surface of the soft palate. The scar is toreduce flexibility of the soft palate to reduce palatal flutter. Huang,et al., report initial results of complete or near-complete reduction insnoring and reduced side effects.

[0010] Surgical procedures such as uvulopalatopharyngoplasty and thoseproposed by Huang, et al., continue to have problems. The area ofsurgical treatment (i.e., removal of palatal tissue or scarring ofpalatal tissue) may be more than is necessary to treat the patient'scondition. Surgical lasers are expensive. The proposed procedures arepainful with drawn out and uncomfortable healing periods. The procedureshave complications and side effects and variable efficacy (e.g., Huang,et al., report promising results in 75% of patients suggesting a fullquarter of patients are not effectively treated after painful surgery).The procedures may involve lasting discomfort. For example, scar tissueon the soft palate may present a continuing irritant to the patient.Importantly, the procedures are not reversible in the event they happento induce adverse side effects not justified by the benefits of thesurgery.

[0011] In pharyngeal snoring, the pharyngeal airway collapses in an areabetween the soft palate and the larynx. One technique for treatingairway collapse is continuous positive airway pressure (CPAP). In CPAPair is passed under pressure to maintain a patent airway. However, suchequipment is bulky, expensive and generally restricted to patients withobstructive sleep apnea severe enough to threaten general health. Huang,et al. at p. 97.

[0012] A technique for snoring treatment is disclosed in commonlyassigned and copending U.S. patent application Ser. No. 09/513,432 filedFeb. 25, 2000. According to certain embodiments of that application,permanent implants are placed in the soft palate to add stiffness to thesoft palate.

SUMMARY OF THE INVENTION

[0013] According to one aspect of the present invention, methods andapparatuses are disclosed for treating a patient's upper airwaycondition such as snoring and sleep apnea. The invention includesselecting a particulate material selected for limited migration withintissue and for encouraging a fibrotic response of tissue to thematerial. A bolus of the particulate material is injected into thetissue area to structurally stiffen the tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 shows, in cross-section, a naso-pharyngeal area of anuntreated patient;

[0015]FIG. 2 shows a soft palate viewed through an open mouth of theuntreated patient of FIG. 1;

[0016]FIG. 3 is a front view of an interior of the mouth shown in FIG. 1and showing an area to be ablated according to a first prior artsurgical procedure;

[0017]FIG. 4 is the view of FIG. 3 and showing an area to be scarredaccording to a second prior art surgical procedure;

[0018]FIG. 5 is a schematic representation of a spring-mass system modelof the soft palate;

[0019]FIG. 6 is the view of FIG. 1 with the soft palate containing animplant in the form of a unit of mass;

[0020]FIG. 7 is the view of FIG. 3 showing the unit of mass of FIG. 6;

[0021]FIG. 8 is the view of FIG. 6 with the soft palate containing animplant in the form of a longitudinal member;

[0022]FIG. 9 is the view of FIG. 7 showing the implant of FIG. 8;

[0023]FIG. 10 is a perspective view of the implant of FIG. 8;

[0024]FIG. 11 is a perspective view of a braided implant;

[0025]FIG. 12 is a side-sectional view of a delivery system for placingan implant in the soft palate;

[0026]FIG. 13 is an exploded view of FIG. 12 following delivery of theimplant from the delivery system;

[0027]FIG. 14 is the view of FIG. 1 with the soft palate containing animplant in the form of a bolus of micro-beads deposited in a linearpath;

[0028]FIG. 15 is the view of FIG. 3 showing micro-beads deposited asspherical deposits; and

[0029]FIG. 16 is a schematic representation showing a patch fordelivering a bolus of micro-beads through a plurality of needles.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0030] A. Physiology Background

[0031] Referring now to the several drawing figures, in which identicalelements are numbered identically throughout, a description of apreferred embodiment of the present invention will now be provided.

[0032]FIG. 1 shows, in cross-section, a naso-pharyngeal area of anuntreated patient. FIG. 2 shows a soft palate SP viewed through an openmouth of the untreated patient. FIG. 1 shows the nose N, mouth M andthroat TH. The tongue T is shown in an oral cavity OC of the mouth. Ahard palate HP (containing a bone B) separates the oral cavity OC fromthe nasal cavity NC. The nasal concha C (soft tissue which defines, inpart, the nasal sinus—not shown) resides in the nasal cavity NC.

[0033] The soft palate SP (a muscle activated soft tissue not supportedby bone) depends in cantilevered manner at a leading end LE from thehard palate HP and terminates at a trailing end TE. Below the softpalate SP, the pharyngeal wall PW defines the throat passage TP. A nasalpassage NP connects the nasal cavity NC to the pharyngeal wall PW. Belowan epiglottis EP, the throat passage TP divides into a trachea TR forpassing air to the lungs and an esophagus ES for passing food and drinkto the stomach.

[0034] The soft palate SP is operated by muscles (not separately shownand labeled) to lift the soft palate SP to urge the trailing edge TEagainst the rear area of the pharyngeal wall PW. This seals the nasalcavity NC from the oral cavity OC during swallowing. The epiglottis EPcloses the trachea TR during swallowing and drinking and opens forbreathing.

[0035] For purposes of this disclosure, the nasal cavity NC, oral cavityOC and throat passage TP are collectively referred to as thenaso-pharyngeal area of the patient with the area including the variousbody surfaces which cooperate to define the nasal cavity NC, oral cavityOC and throat passage TP. These body surfaces include outer surfaces ofthe nasal concha C, the upper and lower surfaces of the soft palate SPand outer surfaces of the pharyngeal wall PW. Outer surfaces meanssurfaces exposed to air. Both the upper and lower surfaces of the softpalate SP are outer surfaces.

[0036] Snoring can result from vibration of any one of a number ofsurfaces or structures of the naso-pharyngeal area. Most commonly,snoring is attributable to vibration of the soft palate SP. However,vibratory action of the nasal concha C and the pharyngeal wall PW canalso contribute to snoring sounds. It is not uncommon for vibratoryaction from more than one region of the naso-pharyngeal area tocontribute to snoring sounds. Sleep apnea can result from partial orfull collapse of the naso-pharyngeal wall during sleep.

[0037] While most of the present discussion will describe placing astiffening implant in the soft palate SP, it will be appreciated thepresent invention is applicable to other regions of the naso-pharyngealarea including the nasal concha C and the pharyngeal wall PW.

[0038] The snoring sound is generated by impulses caused by rapidobstruction and opening of airways. Huang, et al., state the airwaypassage opening and closing occurs 50 times per second during a snore.Huang, et al., utilize a spring-mass model (FIG. 5) to illustrateoscillation of the soft palate in response to airflow (where the softpalate is the ball B of mass depending by a spring S from a fixed anchorA).

[0039] Huang, et al., analogize the shortening of the soft palate SP inuvulopalatopharyngoplasty as effectively raising the critical air flowspeed at which soft palate flutter will occur. The shaded area SA inFIG. 3 shows the area of the trailing end TE of the soft palate SP to beremoved during this procedure. The alternative procedure proposed byHuang, et al., reduces the flexibility of the soft palate SP throughsurface scarring which is asserted as effecting the critical flow speed.The shaded area SA′ in FIG. 4 shows the area to be scarred by thisalternate procedure. In FIG. 4, dashed line L shows the demarcationbetween the soft and hard palates.

[0040] Using the spring-mass model of FIG. 5 as a convenient model ofthe soft palate SP, the present invention is directed to a surgicalimplant into the soft palate SP to alter the elements of the model andthereby alter the dynamic response of the soft palate SP to airflow. Theimplant can alter the mass of the model (the ball B of FIG. 5), thespring constant of the spring S, the dampening of the spring S or anycombination of these elements. Unlike the prior art surgical techniques,the implants that will be described are easy to insert in a smallincision resulting in reduced patient discomfort and are not exposed tothe interior of the mouth (such as the surface scarring of Huang, etal.) as a patient irritant. Also, as will be described, the degree ofdynamic remodeling can be fine tuned avoiding the need for excessiveanatomical modification and are reversible in the event of adverseconsequences.

[0041] B. Disclosure of Copending Applications

[0042] For purposes of illustrative background, FIGS. 6-15 and therelated text below describe certain embodiments of inventions disclosedin the afore-mentioned U.S. patent application Ser. No. 09/513,432.

[0043]FIGS. 6-7 illustrate an embodiment where individual units 10 ofmass (in the form of implantable modular devices such as spheres orimplants of other geometry) are imbedded in the soft palate SP in closeproximity to the trailing end TE. With reference to the model of FIG. 5,the spheres add mass to the mass-spring system thereby altering dynamicresponse to airflow and adding resistance to displacement andaccelerating. The modules are described as any bio-compatible materialsuch as titanium or ceramic.

[0044] The spheres may be sintered or otherwise provided with tissuegrowth inducing material on their outer surface. Such material permitsand encourages tissue in-growth to secure the implant 10 in place. Also,placement of an implant 10 will induce a fibrotic response acting tostiffen the soft palate SP (and further alter the dynamic response andresistance to displacement and acceleration). A sintered or coatedsphere 10 will enhance the fibrotic response and resulting stiffening.

[0045] In addition to modifying the mass profile of the spring-masssystem, the spring component S of FIG. 5 can be modified (alone or incombination with mass modification) to alter dynamic response. FIGS.8-11 illustrate an implant 20 in the form of a flexible strip forplacement in the soft palate. The use of the term “strip” is not limitedto long, narrow implants but can also includes plates or othergeometries implanted to alter the dynamic model of the soft palate SP.

[0046] The strip 20 has a transverse dimension less than a longitudinaldimension. By way of non-limiting example, the strip may have a lengthL_(S) of about 20-30 mm, a thickness T_(S) of about 2-4 mm and a widthW_(S) of 5-10 mm. As shown in FIG. 8, the strip 20 is embedded in thesoft palate SP with the longitudinal dimension L_(S) extending fromadjacent the hard palate HP toward the trailing end TE of the softpalate SP. As shown in FIG. 9, multiple strips 20 may be embedded in thesoft palate SP extending either straight rearward or angled to the sideswhile extending rearward.

[0047] Such stiffening of the soft palate SP stiffens and dampens thespring S in the spring-mass system of FIG. 5 and alters the dynamicresponse of the soft palate SP. The strip 20 may be a spring having aspring constant to further resist deflection of the soft palate SP aswell as urging the soft palate SP to the relaxed state of FIG. 5. Thestiffness of the strip 20, a spring constant of the strip 20, and thenumber of strips 20, are selected to avoid preclusion of closure of thesoft palate SP during swallowing. Examples of suitable materials includetitanium and nitinol (a well-known nickel-titanium alloy). As with theexamples of FIGS. 9 and 10, the strips 20 may be provided with tissuein-growth surfaces or may be coated as desired.

[0048]FIG. 11 illustrates an implant 20′ formed of twisted or braidedfibers 103 a, 103 b. While a single type fiber could be used, theembodiment can be formed of two different fibers 103 a, 103 b braided ortwisted together. One fiber 103 a may be provided for encouragingfibrotic response. Such a fiber 103 a may be polyester or silk suturematerial (in which individual fibers 103 a may be formed of braided ortwisted elements). The other fiber 103 b may be a bio-resorbable fiber(e.g., bio-resorbable suture material which may include naturalmaterials such as collagen or synthetic materials such as the PDS suturematerial). Alternatively, the second fiber 103 b may be a non-resorbablematerial such as polypropylene suture material to provide addedstiffness to the implant. The fibers 103 a, 103 b may be bonded togetheralong the axial length of the implant 102′ to provide added stiffness.

[0049]FIGS. 12 and 13 show a delivery system 100 for placing an implantin the soft palate SP. FIGS. 13-15 illustrate use of the novel deliverysystem 100 with a strip implant 20 (such as implant 20′ of FIG. 11).

[0050] A needle 66 is provided having a ground beveled distal tip 61 forpiercing tissue of the soft palate. The needle 66 is hollow and carriesthe implant 20 in sliding close tolerance. A rod 64 is slidablypositioned in the needle 66 proximal to the implant 20. The implant 20is carried by the needle 66 to a desired implant site within the softpalate. At the desired site, the implant 20 is deployed by retractingthe needle 66 while holding the rod 64 in place. Relative movementbetween the rod 64 and needle 66 causes the rod 64 to dispel the implant20 from the needle 66 without need for moving the implant 20 relative tothe soft palate.

[0051] While advancing the needle 66 through the soft palate, tissue andbody fluids may be inclined to enter the needle 66 and later interferewith discharge of the implant 102 from the needle 66. An optional plug104 is provided to prevent admission of tissue into the needle 66. Theplug 104 is a bio-resorbable material. During discharge, the rod 64 (dueto retraction of the needle 66) urges both the plug 104 and implant 20out of the needle 66. Since the plug 104 is bio-resorbable, it resorbsinto the patient's body over time. The implant 20 provides thetherapeutic effect described above with reference to altering thedynamic response of the soft palate.

[0052] To avoid the plug 104 being urged proximally into the needle 66,the needle 66 includes a first bore 66 a having a diameter approximateto that of the rod 64 and implant 20 and a second bore 66 b at thedistal tip 61. The second bore 66 b is coaxial with the first bore 66 aand is larger than the first bore 66 a so that an annular retaining edge65 is defined within the needle 66. The plug 104 abuts the retainingedge 65 and is restricted from being urged into the needle 66 as theneedle 66 is advanced through the tissue of the soft palate.

[0053] The needle 66 may be porous at the distal tip 61 so the needlewith a loaded implant 20 may be soaked for sterilization if so desired.

[0054] C. Bolus of Particulate Matter

[0055]FIGS. 14 and 15 show an implant 20″ as a bolus of particulatematter. An example of such particulate matter would be micro-beads. Anexample of such is taught in U.S. Pat. Nos. 5,792,478 and 5,421,406.These patents teach carbon-coated metallic or ceramic particles havingcross-sectional dimensions of between 100 and 1,000 microns. Theparticles are carried in a fluid or gel. These patents state that uponinsertion into body tissue, the particles do not migrate significantlyand, apparently due to fibrotic response, the tissue into which theparticles are injected stiffens.

[0056] The particles of U.S. Pat. Nos. 5,792,478 and 5,421,406 are oneexample of particles for stiffening injection. Such particles can alsoinclude ceramic particles or pure carbon or other bio-compatibleparticles. For example, the particles can be vitreous carbon, zirconia(ZrO₂), alumina (Al₂O₃) or polymeric. The particles can be carried in aliquid or gel medium. The particles can have multi-modal particle sizedistributions (i.e., a mix of two or more sizes of particles with thesmaller particles filling interstitial spaces between larger particles).

[0057] The bolus 20″ of particles can be applied by a needle to injectthe bolus 20″ into the soft palate SP. The bolus can be the same volumeas the volume of the implants 20 of FIGS. 8 and 9. With reference toFIG. 15, a multiple of bolus injections can be made in the soft palateresulting in deposition of generally spherical deposits 20′″ ofparticles. Alternatively, an injecting needle can be withdrawn whilesimultaneously ejecting particles for the bolus 20″ (FIG. 14) to bedeposited in a line similar in dimensions to the implants 20 of FIGS. 8and 9.

[0058] The foregoing emphasizes the use of implants to stiffen the softpalate SP. Implants 20″ can be placed in any of the tissue of thenaso-pharyngeal area (e.g., the concha C or other nasal mucosal surface,soft palate SP or pharyngeal wall PW—lateral or posterior) to treatsnoring. Also, such a treatment can stiffen the tissue of the throat andtreat sleep apnea resulting from airway collapse by stiffening theairway.

[0059] While a needle deposition of a bolus of particles is presentlymost preferred, the bolus can be applied in other manners. FIG. 16illustrates deposition of particulates through a patch 200 having avolume 202 containing such micro-beads 204. One side 200 a of the patch200 contains an array of micro-needles 206 communicating with the volume202. The needles 206 may be small diameter, shallow penetration needlesto minimize pain and blood. Examples of shallow, small diameter needlesare shown in U.S. Pat. No. 5,582,184 to Erickson et al. Placing thesurface 200 a against the tissue (e.g., the pharyngeal wall PW as shownin FIG. 16), the needles 206 penetrate the outer surface of the tissuePW. The patch 200 can then be compressed (by finger pressure, roller orthe like) to eject the beads 204 from the volume 202 through theplurality of needles 206. The patch 200 can be provided with interiordividing walls (not shown) so that some of the volume of beads 204 isejected through each needle 206. In the figures, the thickness of thepatch 200 is exaggerated for ease of illustration.

[0060] Stiffening of the naso-pharyngeal tissue provided structure toreduce vibration and snoring. Such structure reduces airway collapse asa treatment for sleep apnea.

[0061] The foregoing describes numerous embodiments of an invention foran implant for the naso-pharyngeal area to treat an upper airwaycondition. Having described the invention, alternatives and embodimentsmay occur to one of skill in the art. It is intended that suchmodifications and equivalents shall be included within the scope of thefollowing claims.

What is claimed is:
 1. A method for treating an upper airway conditionof a patient, said method comprising: selecting an implant sized to beimplanted into a tissue of a pharyngeal wall of said patient, saidimplant having mechanical characteristics for said implant to resistdeflection of said wall and urge a deflected tissue to return to a reststate; and implanting said implant into said tissue of said pharyngealwall.
 2. A method according to claim 1 wherein said implant is metal. 3.A method according to claim 2 wherein said metal is nitinol.
 4. A methodaccording to claim 1 wherein said implant has tissue in-growth areas. 5.A method according to claim 1 wherein said condition is obstructivesleep apnea.
 6. A method according to claim 1 wherein said implant isnot connected to a bony structure.
 7. An apparatus for treating an upperairway condition of a patient, said apparatus comprising: an implantsized to be implanted into a tissue of a pharyngeal wall of saidpatient, said implant having mechanical characteristics for said implantto resist deflection of said wall and urge a deflected tissue to returnto a rest state.
 8. An apparatus according to claim 7 wherein saidimplant is metal.
 9. An apparatus according to claim 8 wherein saidmetal is nitinol.
 10. An apparatus according to claim 7 wherein saidimplant has tissue in-growth areas.